workqueue.c

   1 /*
   2  * Rated submission helpers
   3  *
   4  * Copyright (C) 2015 Jens Axboe <axboe@kernel.dk>
   5  *
   6  */
   7 #include <unistd.h>
   8
   9 #include "fio.h"
  10 #include "flist.h"
  11 #include "workqueue.h"
  12 #include "lib/getrusage.h"
  13
  14 enum {
  15         SW_F_IDLE       = 1 << 0,
  16         SW_F_RUNNING    = 1 << 1,
  17         SW_F_EXIT       = 1 << 2,
  18         SW_F_EXITED     = 1 << 3,
  19         SW_F_ACCOUNTED  = 1 << 4,
  20         SW_F_ERROR      = 1 << 5,
  21 };
  22
  23 static struct submit_worker *__get_submit_worker(struct workqueue *wq,
  24                                                  unsigned int start,
  25                                                  unsigned int end,
  26                                                  struct submit_worker **best)
  27 {
  28         struct submit_worker *sw = NULL;
  29
  30         while (start <= end) {
  31                 sw = &wq->workers[start];
  32                 if (sw->flags & SW_F_IDLE)
  33                         return sw;
  34                 if (!(*best) || sw->seq < (*best)->seq)
  35                         *best = sw;
  36                 start++;
  37         }
  38
  39         return NULL;
  40 }
  41
  42 static struct submit_worker *get_submit_worker(struct workqueue *wq)
  43 {
  44         unsigned int next = wq->next_free_worker;
  45         struct submit_worker *sw, *best = NULL;
  46
  47         assert(next < wq->max_workers);
  48
  49         sw = __get_submit_worker(wq, next, wq->max_workers - 1, &best);
  50         if (!sw && next)
  51                 sw = __get_submit_worker(wq, 0, next - 1, &best);
  52
  53         /*
  54          * No truly idle found, use best match
  55          */
  56         if (!sw)
  57                 sw = best;
  58
  59         if (sw->index == wq->next_free_worker) {
  60                 if (sw->index + 1 < wq->max_workers)
  61                         wq->next_free_worker = sw->index + 1;
  62                 else
  63                         wq->next_free_worker = 0;
  64         }
  65
  66         return sw;
  67 }
  68
  69 static bool all_sw_idle(struct workqueue *wq)
  70 {
  71         int i;
  72
  73         for (i = 0; i < wq->max_workers; i++) {
  74                 struct submit_worker *sw = &wq->workers[i];
  75
  76                 if (!(sw->flags & SW_F_IDLE))
  77                         return false;
  78         }
  79
  80         return true;
  81 }
  82
  83 /*
  84  * Must be serialized wrt workqueue_enqueue() by caller
  85  */
  86 void workqueue_flush(struct workqueue *wq)
  87 {
  88         wq->wake_idle = 1;
  89
  90         while (!all_sw_idle(wq)) {
  91                 pthread_mutex_lock(&wq->flush_lock);
  92                 pthread_cond_wait(&wq->flush_cond, &wq->flush_lock);
  93                 pthread_mutex_unlock(&wq->flush_lock);
  94         }
  95
  96         wq->wake_idle = 0;
  97 }
  98
  99 /*
 100  * Must be serialized by caller. Returns true for queued, false for busy.
 101  */
 102 void workqueue_enqueue(struct workqueue *wq, struct workqueue_work *work)
 103 {
 104         struct submit_worker *sw;
 105
 106         sw = get_submit_worker(wq);
 107         assert(sw);
 108
 109         pthread_mutex_lock(&sw->lock);
 110         flist_add_tail(&work->list, &sw->work_list);
 111         sw->seq = ++wq->work_seq;
 112         sw->flags &= ~SW_F_IDLE;
 113         pthread_mutex_unlock(&sw->lock);
 114
 115         pthread_cond_signal(&sw->cond);
 116 }
 117
 118 static void handle_list(struct submit_worker *sw, struct flist_head *list)
 119 {
 120         struct workqueue *wq = sw->wq;
 121         struct workqueue_work *work;
 122
 123         while (!flist_empty(list)) {
 124                 work = flist_first_entry(list, struct workqueue_work, list);
 125                 flist_del_init(&work->list);
 126                 wq->ops.fn(sw, work);
 127         }
 128 }
 129
 130 static void *worker_thread(void *data)
 131 {
 132         struct submit_worker *sw = data;
 133         struct workqueue *wq = sw->wq;
 134         unsigned int eflags = 0, ret = 0;
 135         FLIST_HEAD(local_list);
 136
 137         if (wq->ops.nice) {
 138                 if (nice(wq->ops.nice) < 0) {
 139                         log_err("workqueue: nice %s\n", strerror(errno));
 140                         ret = 1;
 141                 }
 142         }
 143
 144         if (!ret)
 145                 ret = workqueue_init_worker(sw);
 146
 147         pthread_mutex_lock(&sw->lock);
 148         sw->flags |= SW_F_RUNNING;
 149         if (ret)
 150                 sw->flags |= SW_F_ERROR;
 151         pthread_mutex_unlock(&sw->lock);
 152
 153         pthread_mutex_lock(&wq->flush_lock);
 154         pthread_cond_signal(&wq->flush_cond);
 155         pthread_mutex_unlock(&wq->flush_lock);
 156
 157         if (sw->flags & SW_F_ERROR)
 158                 goto done;
 159
 160         while (1) {
 161                 pthread_mutex_lock(&sw->lock);
 162
 163                 if (flist_empty(&sw->work_list)) {
 164                         if (sw->flags & SW_F_EXIT) {
 165                                 pthread_mutex_unlock(&sw->lock);
 166                                 break;
 167                         }
 168
 169                         if (workqueue_pre_sleep_check(sw)) {
 170                                 pthread_mutex_unlock(&sw->lock);
 171                                 workqueue_pre_sleep(sw);
 172                                 pthread_mutex_lock(&sw->lock);
 173                         }
 174
 175                         /*
 176                          * We dropped and reaquired the lock, check
 177                          * state again.
 178                          */
 179                         if (!flist_empty(&sw->work_list))
 180                                 goto handle_work;
 181
 182                         if (sw->flags & SW_F_EXIT) {
 183                                 pthread_mutex_unlock(&sw->lock);
 184                                 break;
 185                         } else if (!(sw->flags & SW_F_IDLE)) {
 186                                 sw->flags |= SW_F_IDLE;
 187                                 wq->next_free_worker = sw->index;
 188                                 if (wq->wake_idle)
 189                                         pthread_cond_signal(&wq->flush_cond);
 190                         }
 191                         if (wq->ops.update_acct_fn)
 192                                 wq->ops.update_acct_fn(sw);
 193
 194                         pthread_cond_wait(&sw->cond, &sw->lock);
 195                 } else {
 196 handle_work:
 197                         flist_splice_init(&sw->work_list, &local_list);
 198                 }
 199                 pthread_mutex_unlock(&sw->lock);
 200                 handle_list(sw, &local_list);
 201         }
 202
 203         if (wq->ops.update_acct_fn)
 204                 wq->ops.update_acct_fn(sw);
 205
 206 done:
 207         pthread_mutex_lock(&sw->lock);
 208         sw->flags |= (SW_F_EXITED | eflags);
 209         pthread_mutex_unlock(&sw->lock);
 210         return NULL;
 211 }
 212
 213 static void free_worker(struct submit_worker *sw, unsigned int *sum_cnt)
 214 {
 215         struct workqueue *wq = sw->wq;
 216
 217         workqueue_exit_worker(sw, sum_cnt);
 218
 219         pthread_cond_destroy(&sw->cond);
 220         pthread_mutex_destroy(&sw->lock);
 221
 222         if (wq->ops.free_worker_fn)
 223                 wq->ops.free_worker_fn(sw);
 224 }
 225
 226 static void shutdown_worker(struct submit_worker *sw, unsigned int *sum_cnt)
 227 {
 228         pthread_join(sw->thread, NULL);
 229         free_worker(sw, sum_cnt);
 230 }
 231
 232 void workqueue_exit(struct workqueue *wq)
 233 {
 234         unsigned int shutdown, sum_cnt = 0;
 235         struct submit_worker *sw;
 236         int i;
 237
 238         for (i = 0; i < wq->max_workers; i++) {
 239                 sw = &wq->workers[i];
 240
 241                 pthread_mutex_lock(&sw->lock);
 242                 sw->flags |= SW_F_EXIT;
 243                 pthread_cond_signal(&sw->cond);
 244                 pthread_mutex_unlock(&sw->lock);
 245         }
 246
 247         do {
 248                 shutdown = 0;
 249                 for (i = 0; i < wq->max_workers; i++) {
 250                         sw = &wq->workers[i];
 251                         if (sw->flags & SW_F_ACCOUNTED)
 252                                 continue;
 253                         pthread_mutex_lock(&sw->lock);
 254                         sw->flags |= SW_F_ACCOUNTED;
 255                         pthread_mutex_unlock(&sw->lock);
 256                         shutdown_worker(sw, &sum_cnt);
 257                         shutdown++;
 258                 }
 259         } while (shutdown && shutdown != wq->max_workers);
 260
 261         free(wq->workers);
 262         pthread_mutex_destroy(&wq->flush_lock);
 263         pthread_cond_destroy(&wq->flush_cond);
 264         pthread_mutex_destroy(&wq->stat_lock);
 265 }
 266
 267 static int start_worker(struct workqueue *wq, unsigned int index)
 268 {
 269         struct submit_worker *sw = &wq->workers[index];
 270         int ret;
 271
 272         INIT_FLIST_HEAD(&sw->work_list);
 273         pthread_cond_init(&sw->cond, NULL);
 274         pthread_mutex_init(&sw->lock, NULL);
 275         sw->wq = wq;
 276         sw->index = index;
 277
 278         if (wq->ops.alloc_worker_fn) {
 279                 ret = wq->ops.alloc_worker_fn(sw);
 280                 if (ret)
 281                         return ret;
 282         }
 283
 284         ret = pthread_create(&sw->thread, NULL, worker_thread, sw);
 285         if (!ret) {
 286                 pthread_mutex_lock(&sw->lock);
 287                 sw->flags = SW_F_IDLE;
 288                 pthread_mutex_unlock(&sw->lock);
 289                 return 0;
 290         }
 291
 292         free_worker(sw, NULL);
 293         return 1;
 294 }
 295
 296 int workqueue_init(struct thread_data *td, struct workqueue *wq,
 297                    struct workqueue_ops *ops, unsigned max_pending)
 298 {
 299         unsigned int running;
 300         int i, error;
 301
 302         wq->max_workers = max_pending;
 303         wq->td = td;
 304         wq->ops = *ops;
 305         wq->work_seq = 0;
 306         wq->next_free_worker = 0;
 307         pthread_cond_init(&wq->flush_cond, NULL);
 308         pthread_mutex_init(&wq->flush_lock, NULL);
 309         pthread_mutex_init(&wq->stat_lock, NULL);
 310
 311         wq->workers = calloc(wq->max_workers, sizeof(struct submit_worker));
 312
 313         for (i = 0; i < wq->max_workers; i++)
 314                 if (start_worker(wq, i))
 315                         break;
 316
 317         wq->max_workers = i;
 318         if (!wq->max_workers)
 319                 goto err;
 320
 321         /*
 322          * Wait for them all to be started and initialized
 323          */
 324         error = 0;
 325         do {
 326                 struct submit_worker *sw;
 327
 328                 running = 0;
 329                 pthread_mutex_lock(&wq->flush_lock);
 330                 for (i = 0; i < wq->max_workers; i++) {
 331                         sw = &wq->workers[i];
 332                         pthread_mutex_lock(&sw->lock);
 333                         if (sw->flags & SW_F_RUNNING)
 334                                 running++;
 335                         if (sw->flags & SW_F_ERROR)
 336                                 error++;
 337                         pthread_mutex_unlock(&sw->lock);
 338                 }
 339
 340                 if (error || running == wq->max_workers) {
 341                         pthread_mutex_unlock(&wq->flush_lock);
 342                         break;
 343                 }
 344
 345                 pthread_cond_wait(&wq->flush_cond, &wq->flush_lock);
 346                 pthread_mutex_unlock(&wq->flush_lock);
 347         } while (1);
 348
 349         if (!error)
 350                 return 0;
 351
 352 err:
 353         log_err("Can't create rate workqueue\n");
 354         td_verror(td, ESRCH, "workqueue_init");
 355         workqueue_exit(wq);
 356         return 1;
 357 }